Your brain forms connections with many organs aside from the vagina. Pleasant sensations from these can feed into the reward system, which can also be stimulated by non-visceral experiences. The reward system relies on the neurotransmitter dopamine (among others), but that's just one of this chemical's many functions; dopamine is about salience as much as it is about pleasure. In trying to make the vagina/brain/dopamine link central to so many experiences, Wolf ignores all this and a bunch of other messy complexity outside of the tiny central area of this Venn diagram. Note:Circles and their overlap for demonstration purposes only. Do not try this at home.

Share

Your brain forms connections with many organs aside from the vagina. Pleasant sensations from these can feed into the reward system, which can also be stimulated by non-visceral experiences. The reward system relies on the neurotransmitter dopamine (among others), but that's just one of this chemical's many functions; dopamine is about salience as much as it is about pleasure. In trying to make the vagina/brain/dopamine link central to so many experiences, Wolf ignores all this and a bunch of other messy complexity outside of the tiny central area of this Venn diagram. Note:Circles and their overlap for demonstration purposes only. Do not try this at home.

*Earlier this week, I wrote a post criticizing Naomi Wolf's use of science in her book "Vagina: A New Biography." (See Naomi Wolf's "Vagina" and the Perils of Neuro Self-Help, or How Dupe-amine Drove Me Into a Dark Dungeon.) My complaint was that Wolf treated an incredibly complex and ambiguous body of science — the neurobiology of sexual desire and behavior — as settled and simple so that she could present a particular view of sexuality, identity, and consciousness. Though **Wolf draws heavily in her book on the work of Jim Pfaus, a Concordia University psychologist and neurobiologist, I did not evaluate or criticize Dr. Pfaus's particular work, for I wanted to focus on Wolf's treatment of the larger body of science on sexual neurobiology. *

***Dr. Pfaus, however, has now entered the fray directly. Below you will find a rebuttal article that Pfaus wrote, titled "Who's Afraid of the Vagina-Brain Connection" — a play on the play and movie "Who's Afraid of Virginia Woolf" that, perhaps unfortunately, raises the question of whether Wolf is even a faint echo of Woolf. Wolf's book publisher submitted this article for publication here at Wired Science on Thursday. Though we were told that it had been submitted only to Wired Science, the article appeared in the Huffington Post onFriday evening, while I was still preparing a response. *

*I have now incorporated my response into what you find below — Pfaus's article as it appears at HuffPo, but with annotations at some of the many places in which Pfaus misrepresents my argument or says things that strike me as unsupported by the literature. If you want to read the article without my annotations, you may do so at HuffPo — or just read the bold parts below; the whole thing is there. If you want the fact-checked version, see below. *

*Please note, dear reader, that in my post on the science in Wolf's book, I did not argue, as Pfaus suggests below, that there is no neurobiology of sexual desire or behavior, or that neurochemicals or brain-genital-connecetions play no role; of course they do. *

I argued instead that Wolf grossly oversimplifies these very complex systems and their dynamics by ignoring both the youth of the disciplines that studies them and the ambiguous nature of their findings. Along with neglecting this complexity and ambiguity,* Wolf makes all of these systems all about the vagina — a notion consistent with her book goals, but not with science. I'd be just as miffed if she'd made them all about the penis. She approaches three immensely complicated neurobiological systems — brain-organ, reward, and dopamine — and works their narrow overlap in the nether region as if that triangular juncture contained all the most important things about all three of them. A friend drew up a Venn diagram illustrating this:*

Dr. Pfaus or Ms. Wolf may take issue with some of my fact-checking. While I've done my best to be accurate, it's possible I got a couple things wrong — as I said, it's complicated. However, to prove themselvesright, Pfaus and Wolf would need to show not that I'm wrong about any particulars — but that Wolf and Pfaus are right in saying the science unambiguously supports their simplified, narrowly focused view. It's not just the book reviewers who differ Wolf and (as we shall see) Pfaus on this. It's 60 years of research.

So here's Pfaus's article, as submitted, but with my annotations. To make it a bit easier to read, I've put Pfaus's article in bold and my annotations in italics. I have limited my comments to correcting his misrepresentations of or rebuttals to my argument. I have not annotated his critiques of Zoe Heller's' review in the New York Review of Books.

NB: IF YOU WANT JUST THE HEART OF MY RESPONSE, READ "THE GIST," A SECTION ABOUT HALFWAY DOWN LABELED AS SUCH. That deals with the central issue of the Pfaus & Wolf's failure to recognize the science's ambiguity and complexity.

It think it best to state our credentials and conflicting interests up front:

Jim Pfaus is researcher and professor of psychology at Concordia University. Competing interests: According to one of his webpages at Concordia, he holds "consulting grants from several pharmaceutical and biotech companies, for example, Boehringer Ingelheim, Eli Lilly, and Lundbeck, to ... work on the identification of new pharmacological tools to treat male and female sexual dysfunctions."

David Dobbs writes on science and culture here at Wired.com and for publications including the New York Times, National Geographic, Nature, and Slate. He's currently working on a book on how genes and culture shape temperament. Competing interests: He paid just over $10 for a Kindle copy of Naomi Wolf's book, "Vagina: A New Biography," and he resents it.

________Who’s afraid of the vagina-brain connection?

by Jim Pfaus

A curious dialogue has developed with the publication of Naomi Wolf’s new book, “Vagina: A New Biography”, one that seems hell-bent on poking holes in her central theme that the connection between the vagina and the brain influences a woman’s mood and creativity.

Two advance reviews, one by David Dobbs in Wired Science Blogs, and one by Zoe Heller in the New York Review of Books, take Wolf to task for her reliance on neuroscience to help explain the progressive decline that her lower lumbar and sacral nerve blockage had on her sex life, an effect that clouded over her life in general. [DD: **I didn't take Wolf to task for leaning on neuroscience.* I took her to task** for presenting the neurobiology of female sexual response as a settled and unambiguous body of science that explains female sexuality and identity with such completeness that women should rethink their identities and sexual practices.**]* It would have been easy at that time for Wolf to construct a socially acceptable and perhaps even politically correct explanation for her lack of desire and passion. But to her utter astonishment, getting her spinal cord repaired restored her to her former self. This experience had a profound effect on her and prompted her to look deeper at how biology – in this case, the neural reality of her clitoral, vaginal, and cervical sensations – added desire and passion to her life.

Judging from numerous quality-of-life studies done on men with erectile dysfunction who have had it treated, one could easily argue that the penis-brain connection has a major influence on the emotional and intellectual well-being of men. So I must ask why the same would not hold true for a vagina-brain connection? [DD: * Of course brain-genital connections influence our well-being. At issue is how Wolf characterizes those connections and the findings about them.]*

Wolf’s search took her, among other places, to my laboratory. We had been doing research on the role of clitoral and vaginocervical stimulation in the sex and reproductive lives of female rats, work that has been published in high-quality peer-reviewed scientific journals. This work revealed that such stimulation, when applied in the right way, induces a state of sexual reward that conditions place and partner preferences (the latter of which was unexpected in an allegedly promiscuous and polygamous species). Taken together with previous work from my laboratory showing the profound role of dopamine and opioid neurotransmitters in both male and female sexual behavior, and in the context of a more general scientific literature in animals and humans showing that blockade of those transmitters induces varying degrees of an “anhedonic” state akin to depression in which reward does not occur and animals do not focus their attention toward it anymore, it became clear to Wolf that these neurochemicals were important parts of the sexual desire and pleasure systems of the brain. [*DD: Yes, neurochemicals are important parts of desire and pleasure. If she'd stopped there, I'd have no objections.**] They were activated by clitoral, vaginal, and cervical stimulation, something that had gone missing in action due to Wolf’s progressive deterioration of her spinal cord. [DD: Ditto.] She was thirsty for knowledge about how those sensations activated the brain. [DD: Fine. An understandable curiosity.] *She spent an enormous amount of time carefully making herself aware of the scientific literature on the neuroanatomy and neurochemistry of desire and reward and she and I had numerous discussions about how these things work, and how they can be disabled – by culture, by experience, by events that ultimately perturb neurons in specific brain networks. [DD: All good so far.]

In his review, Dobbs argues that Wolf oversimplifies the role of dopamine, noradrenaline, opioids, and oxytocin. [*DD: Yes, I did. ]*Yet the feelings associated with the decline and resurgence of her sexual self were very real, and I would argue that her take on the role of those neurotransmitters is entirely consistent with current conceptions of their role in, among other things, sexual behavior, feeding, and drug addiction. [*DD: The reality of Wolf's feelings have nothing to do with whether she got the science right.]. *Heller is more allegoric in her review. She takes Wolf to task for ignoring “common sense and logic” and for “drinking shallow drafts from the fountains of evolutionary biology and neuroscience…” because emotional states like desire, events like orgasm, and the interpretation of pleasure are obviously too complex to be left to anything reductionist.

Certainly these are socially constructed at several levels, but there is no denying the reality of Wolf’s spinal condition or the way that her sexual and creative feelings came thundering back when the problem was fixed. Is Wolf right in regarding dopamine as the “ultimate feminist neurochemical”? It is certainly unlikely that sea slugs and nematode worms are feminists. But can’t we allow an accomplished writer and social critic a little poetic leeway to make a point? [DD: Wolf* took a LOT of leeway — and, if I may take some myself, she sailed through all of it and ran the ship onto the rocks.]. *If dopamine mobilizes attention to reward, and sexual reward is something that has been elusive for so many women for a slew of cultural and experiential reasons (all of which impinge on the kind of sexual stimulation women learn to allow themselves to make or receive), then the lack of dopamine transmission in the brain in a sexual circumstance would likely lead to disorders of desire, and de facto little or no sexual reward since the person in question would either no longer get herself entangled in a sexual circumstance, or if she did, no longer care if she “spread her legs and thought of England.”

[DD: Pfaus writes that a lack of dopamine "would likely lead to sexual disorder..." This is a key* phrase and raises the problem. Speaking of likelihoods is fine. That's what science is — an exploration of possibilities. Only rarely does science bring certain, simple answers. *

*Pfaus accuse me here of dismissing discussion of possibilities, but I did no such thing. It's Wolf's substitution of certainties for possibilities that bug me. Studies of these dynamics are generally mixed and sometimes contradictory. Some studies, for instance, including one by Pfaus himself, show that dopamine dynamics that are usually considered 'stimulatory' can decrease sexual behavior and that dopamine dynamics thought to be inhibiting can increase sexual behavior. And even that study, in its abstract, describes its findings in phrases such as "These results suggest that the ratio ... is critical ... and may..." have such and such an effect. This is as it should be: suggestions and possibilities — but Wolf, writing of them, presents them as givens and certainties.] *

Heller should recognize her own glass house before throwing stones. There are more than a few straw men set up in her review. One of the criticisms she levels at Wolf, and is reiterated by Dobbs in his blog, is the “upsuck theory” of orgasm, and how it could facilitate pregnancy. Heller dismisses this as being derived from one study from the 1990s with a single subject. Dobbs suggests that Wolf should have read the literature more carefully. Yet a cursory review of this literature on Pub Med shows papers from Shafik and others that studied specifically this cervico-uterine reflex (sometimes referred to as the “Shafik reflex”). This reflex clearly increases sperm transport into the uterus, and was studied in many women, not just one.

Now, does the cervico-uterine reflex actually influence rates of pregnancy? It could. And it could therefore be a reproductively-relevant reason (one of several out there in the scientific literature) to answer the seemingly mysterious question of why women have orgasms. And that is as far as Wolf takes it. Cervical stimulation has long been known in animals to increase sperm transport and induce neuroendocrine reflexes that result in increased prolactin secretion from the pituitary, two essential steps to initiating and maintaining pregnancy. Cervical stimulation occurs during heterosexual sex through mechanical stimulation by a penis and prior to and during orgasm as a “dipping reflex” that is part of a “vaginal tenting” response. Does this make orgasm necessary for pregnancy? Not at all. Nor is Wolf saying so. It simply makes cervical stimulation (and in reality, stimulation of the pelvic nerve) a potentially important promoter of pregnancy. Is orgasm the only reason women have sex? Clearly not. And Wolf does not try to make that case either in her book. Sexual stimulation has many rewards, orgasm being one. Now, saying that, there is no doubt that orgasms feel good and that they are associated in female rats and women with the rush of opioid release in the brain.

Dobbs states that “Neurocritic says he can find little peer-reviewed literature to back Wolf’s claims.” Really? I am not sure where he looked. As with the Shafik reflex, a simple Pub Med search on the role of dopamine, oxytocin, and opioids in the sexual behavior of rats, voles, monkeys, and humans reveals plenty of peer-reviewed literature to back Wolf’s take on the role of these neurochemicals.

THE GIST: [DD: Both Neurocritic and I know quite well that PubMed searches for major transmitters in sexual behavior will get hundreds or thousands of results. When we wrote our posts a day before the book's publication, however, Neurocritic and I were both limitied to specific statements Wolf made about* dopamine's role *in the few pages of her book then accessible through the publisher's site. I've since bought the book but remain unimpressed. **

**Let's look at this more broadly. *Pfaus is correct in saying there are quite a few studies about dopamine and sex. But taken together, those studies present an ambiguous and tentative set of findings about exactly how dopamine and other neurotransmitters affect *

For instance, I just did a PubMed search for "dopamine sexual desire" and filtered it for review articles (the kind that survey broad swaths of literature) with open-access full-text results. The top hit is "Managing low desire in women," quite relevant to Wolf's subject and Pfaus's science, by Kate Maclaren and Nick Panay, published September 2011. Here's a representative sampling of what it says about dopamine (emphasis mine):

" A critical balance is required between the excitatory pathways, primarily controlled by the dopaminergic system, and inhibitory pathways of the serotonergic system, for normal sexual function. Animal models have suggested that dopamine acts to enhance sexual desire and excitement [19],…

*This Maclaren and Panay article, having described the broader literature it surveyed as suggestive but inconclusive, then describes two recent studies in which buproprion (sold most prominently as the antidepressant Wellbutrin), "which causes dopamine and noradrenalin reuptake inhibition and, therefore, acts on the excitatory pathways of sexual desire," generated "significant improvement across all domains of sexual functioning and a reduction in distress." *

That finding lends some support to Pfaus's contention that dopamine may raise desire — although, please note that noradrenalin was tweaked here too; and other studies have found amphetamines have a similar effect; and yet others have found yet that yet things can (but don't always) affect desire; and that these were just two studies, and the evidence base wasn't good enough to get bupropion approved for as a treatment for sexual dysfunction. If it had been, GlaxoSmithKline would not have had to pay the U.S. government $3 billion as a penalty for marketing it as such. Note too that buproprion also creates side effects that can include seizures, anxiety, sweating, reduced food intake, decreased sleeping, and panic attacks. Are we to see those too as essential parts of female identity? I hope Wolf would say No.

It's complicated. Drugs are unpredictable because neurotransmitters are unpredictable and do many things. And many, many* things can affect desire — and always through complicated pathways. This is precisely why, as almost any Casanova or yoni tapper could tell you, pretty much nothing affects desire in all women all the time — and for that matter, pretty much nothing affects desire in even any given woman all the time. That would make life way too easy! Love is many-splendoured; sex is multifactored. *

Meanwhile, less friendly to Pfaus's assertion is the only review study that the Maclaran and Panay study cited on this literature of dopamine and desire. This one kills. This study, also from 2011, examined all findable studies of the effect on sexual function of clinical trials of dopamine-targeting drugs between 1950 and 2010 — 60 years of dopamine's effect on sex — and found the evidence base so thin and ambiguous that it "prevent[s] adequate interpretation." Obviously Pfaus disagrees; but that's my point. On one hand we have 60 years of research that defies simple interpretation; on another we have Pfaus and Wolf, who say that dopamine levels determine desire and satisfaction in straightforward fashion — and, in Wolf's case, that it's a feminist molecule that is the key to female sexuality, identity, and even consciousness.

Oh but wait; we were talking science. Another review my search turned up,* by J.A. Simon of George Washington University, conveys well how the complex, multifactorial nature of sexual desire and satisfaction makes it hard to pin down any one system, much less a neurotransmitter or two:*

Causes of low desire include chronic medical conditions, medications, surgeries, and psychosocial factors, but not necessarily increased age; both pre- and postmenopausal women can have HSDD, although the frequency appears to vary by age. Sexual function requires the complex interaction of multiple neurotransmitters and hormones, both centrally and peripherally, and sexual desire is considered the result of a complex balance between inhibitory and excitatory pathways in the brain. For example, dopamine, estrogen, progesterone, and testosterone play an excitatory role, whereas serotonin and prolactin are inhibitory. Thus, decreased sexual desire could be due to a reduced level of excitatory activity, an increased level of inhibitory activity, or both.

*This confronts the complexity as it should. So do the laments in these papers about how far we are from reliably figuring out the cause of sexual dysfunction or finding reliable ways to address it. *These studies and reviews are consistent in finding that drugs that affect dopamine levels produce mixed results, and that, in humans, these drugs sometimes do better than placebos do in improving sexual desire or response, but seldom by much. Sixty years of research on dopamine and sex, in other words, consistently challenge the idea that simply changing dopamine levels changes sexual desire.

*So, yes, again, dopamine is a 'cause-effect' molecule, but not in the simple way Wolf portrays in "Vagina" and Pfaus seems to argue here. *

*Now, this is complicated stuff. Really complicated stuff. I don't ask that a popular science book explain every bit of complexity or constantly beat us over the head with it. But I do ask that a popular science book actively acknowledge the complexity of such things, rather than brush it aside, and that it not rush to reduce complex interplays of chemicals and synapses to neat, deterministic statements such as Wolf's "A woman with low dopamine will have low libido and depression." That's simply not true. She might be more likely to; but by no means will it be guaranteed. *

Back to Pfaus:

__This is definitely not, as Dobbs states, “…quick-dip pop-science.” At least Dobbs doesn’t doubt my scientific credentials, though he seems to doubt things that I say. In one, he quotes me as saying __

__“You could call dopamine the ’cause-effect’ chemical.’ This is quite true at some level or even several levels; the chemical causes things to happen. But what effects does it cause? Wolf jumps from Pfaus’s statement, without setting it directly into context, to state in essence that dopamine is the key to “good orgasmic sex.” __

Wolf did indeed set it into context, at the very beginning of the book, in the description of her odyssey back to nerve function, from sexual stimulation colored dimly grey to the resurgence of orgasms colored like Peter Max posters.* *

What does dopamine contribute to this? The intense desire that amazing orgasms ride on. Anyone who has ever had great sex in a long-distance relationship knows the cocaine-like anticipation, the breathtaking intensity of that first touch and kiss. That is driven in an important way by dopamine.

[*DD: **Yes, dopamine plays a huge role in anticipation, but in many, many realms, not just in sex. Even in sex, it doesn't always behave as Pfaus insists. One 2005 study of dopamine's effect on sexual response in patients treated for Parkinson's, for instance, found that it increased sexual response in men but not in women (!!!): "The counterpart of such regulation of the genital arousal by dopamine has not yet been established in females." This is what I mean by ambiguous findings: As in, opposite to what Pfaus is arguing as a proven dynamic. __ *__

Rats show homologous behaviors in anticipation of sex, behaviors that we can block with very low doses of dopamine antagonist drugs. We can block opioid receptors with selective drugs that subsequently block the development of conditioned place and partner preferences, essentially blocking the effect of sexual reward. In fact, female rats that have their opioid transmission blocked repeatedly during sex stop wanting to have sex anymore, despite hormone priming that would normally bring them fully into heat. Instead of soliciting and controlling sexual contact with males, sexually nonrewarded females fight and reject the males’ advances. Can we conclude then that dopamine is the key to desire, and that opioids are the key to reward? I would think that we could. There is enough pharmacological data from the psychiatric literature on people taking dopamine antagonists as major tranqulizers, or from people suffering depression, to know that dopamine is a major player in desire, and that the opioid rush produced by drugs of abuse, or natural rewards like sex and orgasm, not only feels good itself, but sensitizes dopamine release that augments the subsequent experience of desire and focuses it on the stimuli associated with reward. Thus, when Dobbs states that Wolf is flat-out wrong in her contention that “A woman with low dopamine will have low libido and depression,” I must remind him that this is exactly what the literature suggests, especially in a sexual circumstance. I must remind Pfaus to read the two 2011 reviews I discuss above.

__Wolf merges the science of sexual arousal, desire, and pleasure, with her experiences of different types of orgasms and especially the vaginal “goddess complex” that is tapped doing tantric sex. Some may well feel that this is science for the sake of pop psych, after all, how can such a thing be? Let me make an analogy: Is a placebo drug effect “real”? Indeed it is. Scientists have shown that belief in, say, a potential painkiller’s ability to reduce pain actually causes neural systems that modulate pain (e.g., opioids) to be activated, thus contributing to a placebo effect that in some people can be as effective as the drug itself. Does this mean that the drug is ineffective? No, only that in some people the physiologic effect belief is powerful. Tantric sex seeks to get people to use their whole bodies as conduits of sexual “energy” in sexual circumstances. We can dismiss this as pandering to the placebo, but some people swear by it because they have transformative experiences doing it. Those are as real as any drug. In the end, everything, from drugs and hormones to priming cues to beliefs, are ultimately the sum of the action of appropriate neural systems. However, cognitive neuroscience still has not solved the problem of why one’s conscious and verbal self-appreciation of this is a kind of quantum mechanics goes beyond our understanding of the individual parts (though it is currently very hard to study more than one neurochemically-defined part). __

As Forrest Gump might have said, “You never know where you are ‘til you get there.” People that have never had orgasms do not know orgasms… well, until they have one, and then are forever changed. Experience changes people in often profound ways. Our brain allows us to scale our orgasms, as we do the incentive quality of the food we eat, not just as good or bad, but on an interval from say 0 to 10. And we can get really good at knowing when an orgasm is a 1 or 5 or 10. But… give a new lover a try, and the orgasms that result may well transform the scaling, such that he or she cranked it up to 11, or what was previously a 10 is now a 7. Sometimes, the quality can change the perception completely into something entirely new. That is part of what the purveyors of tantric sex are trying to do. And for those in whom it happens, a belief in the power of the procedure comes naturally, despite it being entirely circular. But our brains are wired for circular reasoning. We could not have Pavlovian conditioning without that capability. Conversely, for those who cannot or will not look into the eyes of the tantric teacher for 10 minutes before he states “Welcome Goddess”, the experience can be a waste of time and money. It can be worse: one person’s aphrodisiac can be another’s cause of dysfunction. Cocaine is a great example of that. Understanding how cocaine works does not itself mean that we can predict whether it will aid in great or terrible sex, but it will allow us to place the experience in a context or as a function of temperamental variables that may well make the predictions fall into place.

Unlike Dobbs and Heller, I applaud Wolf’s foray into neuroscience and its use in her book. I suspect that any embellishing was done for effect, to sensitize readers to a new and integrative way of viewing our sexual selves, and to call women to sexual action and exploration that is in their control, as it is in my female rats. [*DD: **Wolf did not embellish; she misrepresented. And she did so because only through grossly oversimplifying and misrepresenting could she harness an ambiguous, highly complex arena of science to support a sweeping, simplistic, and decidedly unambiguous argument about sexual response, identity, and even consciousness.] *I am sure that was not an easy path for Wolf to take, intellectually or politically. Like any curious human being, she needed to understand what happened to her. She tried to find enlightenment in a review of the social and political constructions of desire, pleasure, control, orgasm, clitoris, and vagina, but that only took her so far. The rest came from a review of the current scientific literature on how the clitoris, vagina, and cervix are connected to the brain, how their stimulation and orgasm activate the brain and pathways of desire and reward, and from her own subjective sexual reawakening. Adding it to her narrative allows the reader to think beyond restrictive cultural definitions of what women should be feeling sexually, to a growing basic science of how their sexual sensory organs work, how they are connected to their brains, and how individual differences in neural innervation of those organs can lead to differences in how sensations are felt and ultimately interpreted and integrated into their sexual selves. Dobbs states that this drives his dopamine “down into a dark and mostly unsexy dungeon”. Fair enough. But to me it only opens up new vistas of wonder and inquiry. Rather than taking the nescient view that a potential vagina-brain connection is something too complex to understand, or worse, a dreaded opening of Pandora’s Box, may I suggest that we embrace it, as we do the penis-brain connection, as a new empowerment of knowledge about sexuality.

[*DD: Pfaus ends as he begins: By misrepresenting my argument. I'm all for a science of wonder and inquiry. I am not for presenting embryonic and ambiguous science as mature and certain, or for using grossly oversimplified versions of complex dynamics to try to sell books, new and limited visions of our fellow humans' sexuality, or treatments — yoni-tapping, self-help books, or new drugs — that purport to address dynamics that we don't yet understand.] *